The invention relates to a control valve, which is movable back and forth and arranged to open and close pressure channels leading to a percussion device. Furthermore, the invention relates to a method of controlling a working cycle of a percussion device, and to a percussion device for breaking rock.
In rock breaking, percussion hammers and rock drills are used that are equipped with a percussion device for giving impact pulses to the rock through a tool. The percussion device comprises an impact element, such as an impact piston, whose working pressure surfaces can be affected by a pressure medium, the impact element being arranged to produce the necessary impact pulses. The pressure medium that acts on the impact element can be guided by a control valve, which is connected to open and close pressure medium channels. It has been found that particularly when the control valve has to be able to open and close very fast, a high amount of kinetic energy binds to the valve due to the valve mass and velocity. Thus a problem associated with existing control valves is that their use requires a high amount of power.